The potential for generating energy using the heat energy found within the earth, sometimes called “heat mining,” has been the subject of much investigation over many years. If they can be tapped efficiently, our geothermal resources represent a practically inexhaustible source of non-fossil fuel.
Prior attempts to exploit geothermal energy have encountered various problems. Most of the problems could have been anticipated from the nature of the unstable rocks where the projects have been located. Some have attempted to recover geothermal energy from locations where unusually high temperatures are found relatively close to the surface. These geologically active areas typically are characterized by earthquakes, faulting, or igneous flows of molten material. It is these conditions which foretell an unsatisfactory outcome. Unstable geologic formations, where recent tectonic activity has taken place, normally are very fractured and highly mineralized with polluting formation fluids. Fractured formations release hydrogen sulfide and other undesirable gases, which should not be released into the atmosphere and which generate an unpleasant odor for miles around the site. Steam produced from water passing through these fractured formations may be highly mineralized and corrosive on turbines and generators.
In a conventional coal or gas fired electrical generator, the water is first heated to high pressure hot water, or steam at atmospheric pressure. A large portion of the energy from the coal or gas used to heat the water is lost as exhaust up the smoke stack. Water is heated to form thermal energy that is converted to mechanical energy, which drives a generator to form electrical energy. The big losses of energy occur when the cold water becomes high pressure steam. In conventional generator systems, more than half the energy is being wasted. Consequently, the maximum efficiency of traditional coal fired generators usually is less than 40 percent.
Thus, in spite of the efforts to date, there remains a need for a geothermal energy recovery and conversion system and method that is energy efficient, cost effective, and environmentally friendly. Coal is the most cost effective system of electrical generation in use today, but it produces a high degree of pollution. The emissions into the atmosphere, via the smokestack, are many including residual radioactive material carried in the coal. With present generating plants costing in the 750 million dollar range, the present invention provides a viable option for energy production.